Cracks that form within materials can be difficult to detect and almost impossible to repair. A successful method of autonomically repairing cracks that has the potential for significantly increasing the longevity of materials has been described, for example, in U.S. Pat. No. 6,518,330. This self-healing system includes a material containing, for example, solid particles of Grubbs catalyst and capsules containing liquid dicyclopentadiene (DCPD) embedded in an epoxy matrix. When a crack propagates through the material, it ruptures the microcapsules and releases DCPD into the crack plane. The DCPD then contacts the Grubbs catalyst, undergoes Ring Opening Metathesis Polymerization (ROMP), and cures to provide structural continuity where the crack had been.
A challenge in designing this type of self-healing composite material is that healing usually is possible only when a crack propagates through the bulk matrix material. Thus, the composite material is typically unresponsive to damage that occurs at an interface, such as an interface between the matrix material and a reinforcing material, or an interface between two layers of matrix materials. Since interfacial failure is an important failure mechanism in reinforced composite materials, self-healing of this damage may allow for a further increase in the longevity of a composite material by preventing catastrophic growth of smaller cracks.
It is desirable to provide a self-healing reinforced composite material that can autonomically self-heal when at least a portion of the reinforcing material and the matrix material are separated. It is also desirable to provide a functionalized reinforcing material that can be combined with a matrix to provide such a self-healing composite reinforced material.